A Preliminary Discourse on the Study of Natural Philosophy

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Longman, Brown, Green & Longmans, 1840 - 372 páginas

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Página 8 - The character of the true philosopher is to hope all things not impossible, and to believe all things not unreasonable.
Página 162 - ... single and perfectly definite new circumstance, and manifesting the effect so rapidly that there is not time for any other material change in the pre-existing circumstances. " It is observed that dew is never copiously deposited in situations much screened from the open sky, and not at all in a cloudy night ; but if the clouds...
Página 158 - Many of the new elements of chemistry have been detected in the investigation of residual phenomena. Thus Arfwedson discovered lithia by perceiving an excess of weight in the sulphate produced from a small portion of what he considered as magnesia present in a mineral he had analyzed.
Página 10 - ... the grand, and, indeed, only character of truth, is its capability of enduring the test of universal experience, and coming unchanged out of every possible form of fair discussion.
Página 287 - geology, in the magnitude and sublimity of the objects of which it treats, undoubtedly ranks, in the scale of the sciences, next to astronomy...
Página 7 - ... places the existence and principal attributes of a Deity on such grounds as to render doubt absurd and atheism ridiculous, it unquestionably opposes no natural or necessary obstacle to further progress : on the contrary, by cherishing as a vital principle an unbounded spirit of inquiry, and ardency of expectation, it unfetters the mind from prejudices of every kind, and leaves it open...
Página 51 - ... as a specific or natural antagonist against that odious deformity. It is thus that any accession to our knowledge of nature is sure, sooner or later, to make itself felt in some practical application, and that a benefit conferred on science, by the casual observation or shrewd remark of even an unscientific or illiterate person, infallibly repays itself with interest, though often in a way that could never have been at first contemplated.
Página 50 - Between the physical sciences and the arts of life there subsists a constant mutual interchange of good offices, and no considerable progress can be made in the one without of necessity giving rise to corresponding steps in the other. On the one hand, every art is in some measure, and many entirely, dependent on those very powers and qualities of the material world which it is the object of physical inquiry to investigate and explain...
Página 25 - ... millions of millions of times ; of yellowness, five hundred and forty-two millions of millions of times ; and of violet, seven hundred and seven millions of millions of times per second.* Do not such things sound more like the ravings of madmen, than the sober conclusions of people in their waking senses...
Página 60 - The combustion of seven bushels of coal would suffice to raise it to the place where it hangs. The great pyramid of Egypt is composed of granite. It is 700 feet in the side of its base, and 500 in perpendicular height, and stands on eleven acres of ground. Its weight is, therefore, 12,760 millions of pounds, at a medium height of 125 feet ; consequently it would be raised by the effort of about 630 chaldrons of coal — a quantity consumed in some foundries in a week.

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